2) In a small saucepan melt the butter with the water and add the light brown sugar. Stir well with a whisk over a medium heat until the sugar is completely dissolved to make a nice smooth caramel, about 3 to 4 minutes. Pour into a round 24cm nonstick cake pan.
3) Arrange the pineapple circles evenly in the caramel, 1 at the centre and 5 around the outside, and press down so they are submerged in the caramel. Place 1 maraschino cherry in the centre of each pineapple ring.
Make the batter:
1) Sift the flour and baking powder together. In a mixer cream the butter and granulated sugar together until light and fluffy, about 4 minutes.
2) With the mixer on low, add the eggs 1 at a time. Add half the buttermilk and vanilla then half the flour. Add the remaining buttermilk and then the remaining flour.
3) Pour the batter into the cake pan over the caramel and pineapple. Spread out evenly with a rubber spatula.
4) Place the cake pan on a roasting tray, to catch any caramel that may bubble over, and bake in the oven for approx 1 hour. The cake should be nice and golden on top and puffed up slightly. When gently pressed in the centre it should bounce back.
5) Allow to cool slightly for about 1 minute, before inverting onto a cake plate. Dust very lightly with icing sugar and serve each slice with a scoop of frozen yogurt.